Ski made of synthetic resins

ABSTRACT

A ski made of synthetic resins composed of upper and lower plates and side plates defining the outer shape of the ski, wherein the upper and lower plates are provided with a plurality of longitudinal ribs at the inner surfaces thereof each having a cross section of a series of projection adapted to mesh with each other provided on the opposing plate, said ribs being provided with such incisions therealong that allow bending of the upper or lower plate without restriction due to the ribs, and the ribs of the upper and lower plates are bonded together to form originally curved ribs while the upper and lower plates are shaped to a required profile in a mold under a heated and compressed condition.

States Patent Nalramnra et al,

[451 Jan, 18, 1972 [54] Sm MADE OF SYNTHETIC RESINS FORElGN PATENTS on APPLICATIONS [72] Inventors; Syuhei Nakamura; Himnobu Takakamo, 948 Canada 1.13 both f Shimodatmshi, Ja a Add. 87,350 6/1966 France... .....280/11.13 0 1,059,670 11/1953 France... ..280/l1.13 [73] Assrgnee: Hitachi Chemical Company, Ltd., Tokyo,

Japan Primary Examiner-Milton Buchler [22] Filed: Oct 13, 1969 Assistant Examiner-Paul E. Sauberer Attorney-Craig, Antonelli & Hill [21] Appl.No.: 865,903

[57] ABSTRACT Foreign Application Priority Data A ski made of synthetic resins composed of upper and lower Oct 16 1968 Japan 43/89738 plates and side plates defining the outer shape of the ski,

wherein the upper and lower plates are provided with a plu- [52] U S Cl 280/] 1.131 rality of longitudinal ribs at the inner surfaces thereof each [51] A63c 5/12 having a cross section of a series of projection adapted to i i mesh with each other provided on the opposing plate, said ribs [58] Field of Search ..280/1 1.13, 1 1.13 L, 9/310 being provided with Such incisions therealong that allow bend ing of the upper or lower plate without restriction due to the [56] References Cited ribs, and the ribs of the upper and lower plates are bonded UNITED STATES PATENTS together to form originally curved ribs while the upper and lower plates are shaped to a required profile in a mold under 21 2,371,305 3/1945 Marks .280 1.13 X heated and compressed condition 7 Claims, 3 Drawing Figures 5 1 i 5 i v n i l A j A 3 PATENTEU m1 8I972 INVENTORS syuusr NAKAMHRA and HIRONDUH TAKAKAMO ATTORNEY Slfill MADE OF SYNTHETIC RESINS BACKGROUND OF THE INVENTION are bent upwardly and central portions thereof are curved to be slightly upwardly convex, and the condition of the central curvature is considered to be an important factor fora good operation of skis regarding slidability, steerability, etc'. In case of skis made of wood or synthetic resins, the front end and central curvatures are formed by correspondingly curved molds under a heated and pressurized condition. However, the skis thus formed to their required curvatures are not completely free from gradually progressing straightening of the curved portions due to restoring nature of wood or synthetic resins in a long period of use. Therefore, it has been a common method of storing a pair of skis to join the lower surfaces of the skis with each other while inserting properly shaped spacer blocks in the spaces formed between the front end and central curved portions of the pair of joined skis and to tie them fast together by strings or ropes thereby to prevent the above-mentioned straightening of the curvatures.

SUMMARY OF THE INVENTION Accordingly, a main object of this invention is to remove the above-mentioned defect in the conventional skis and to provide an improved ski especially made of synthetic resins having good elasticity and high stability of an originally formed shape of curvature for a long period of use.

The above-mentioned object of this invention is accomplished according to this invention by a ski made of synthetic resins comprising upper and lower plates combined with each other to define upper and lower surfaces thereof and two sideplates defining side surfaces thereof, characterized by a plurality of longitudinal ribs formed on inner surfaces of said upper and lower plates, said ribs being provided with such traverse incisions along axial length thereof that allows bending of said upper and lower plates to each required profile with substantially no restriction by said ribs, wherein said ribs formed on said upper plate are bonded with said ribs formed on said lower plate while said upper and lower plates are kept at each required bent profile.

Another object of this invention is to provide a ski of the above-mentioned kind which has a light but strong structure.

Other objects and advantages of this invention will become apparent from the following descriptions of a preferred embodiment of this invention made with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing;

FIG. 1 is a cross section of a ski according to this invention;

FIG. 2 is a side view of upper and lower plates before their combination into the ski as shown in FIG. ll;

FIG. 3 is a longitudinal section through a couple of molds and the ski formed therein from the upper and lower plates as shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT ln FIGS. 1 to 3, reference numerals 1 and 2 designate upper and lower plates of a synthetic resin, respectively, which define upper and lower surfaces of a ski having a vertically sectional contour as shown in FIG. 3. The upper and lower plates l and 2! are each provided with a plurality of longitudinal ribs 3 which have cross sections comprising a series of jags as shown in FIG. I, wherein the ribs 3 of the upper and lower plates are adapted to correspondingly mesh with each other. In the embodiment shown in the drawing, the ribs provided at both edge portions 4 of the upper and lower plates are extending over the whole length of the ski and adapted to close the side openings formed between the upper and lower plates. The ribs 3 provided at inner regions may be arranged at any preferable position over any preferable length. The jags in the shown embodiment are wedges each adapted to tightly mesh with corresponding ones formed on the opposing plate, but the ribs may have any other cross section such as a series of rectangles as long as they are adapted to tightly mesh with each opposing ones.

As shown in FIG. 2, the ribs 3 are provided with incisions 5 and 6 along the length thereof. These incisions are necessary since the upper and lower plates l and 2 are curved as shown in FIG. 3 in a set of molds 9 to have a desired profile as a ski. Rib portions where the plate is curved inwardly concave are provided with V-shaped notches 5 to allow contraction of rib edges, while rib portions where the plate is curved inwardly convex are provided with mere cuts 6 for the purpose of simplicity. Of course the mere cuts 6 may be replaced by the V shaped notches 5. The incisions of a rib are preferably arranged as longitudinally shifted from the incisions provided at another rib with which it meshes.

The upper and lower plates l and 2 provided with the ribs 3 cut to rib portions of each proper length are set in the molds 9 defining a void corresponding to a ski having a desired shape and permanently formed to the shape under a heated and pressurized condition, wherein the ribs of the upper and lower plates meshing with each other are firmly bonded with each other to form stable curved ribs which guarantee a high stability of the formed curvature of the ski.

Reference numeral 10 designates sideplates which are adapted to close the side openings formed between the upper and lower plate. The sideplates 10 may be made of a synthetic resin or other suitable materials. Inner spaces left between the upper and lower plates may be filled with a foamed synthetic resin.

Since the ski according to this invention is formed of the upper and lower plates and the sideplates defining the outer shape of the ski as well as supporting tension and compression forces due to bending of the ski in the most effective manner and the longitudinal ribs substantially carrying load exerted on the ski as well as keeping the required curvature of the ski, leaving a large inner space not filled or filled with a light foamed synthetic resin, the ski is light and nevertheless has a strong structure, and a high stability of the originally formed shape of the ski is guaranteed. Furthermore, since the ski according to this invention is manufactured in a simple process of bonding the upper and lower plates together in one step of operation, uniform products are obtained at a relatively low cost. l

What is claimed is:

11. A ski of synthetic resinous material comprising upper and lower plates combined with each other to define upper and lower surfaces of said ski, two sideplates defining side surfaces of said ski, and a plurality of longitudinal ribs successively and separately formed on each of the inner surfaces of said upper and lower plates, each of the ribs of said upper plate being oppositely disposed and bonded to a corresponding rib of said lower plate thereby defining a void between each successive pair of bonded ribs, said ribs being provided with transverse incisions along the axial length thereof to permit substantially unrestricted bending of said upper and lower plates to the required profiles.

2. A ski according to claim 11, wherein each of said ribs has a cross section including at least two jags, the jags formed on the oppositely arranged ribs of said upper and lower plates being adapted to mesh with each other.

3. A ski according to claim 1, wherein the transverse incisions provided in the ribs formed on said upper plate are longitudinally shifted from those provided in the ribs formed on said lower plate.

4. A ski according to claim 1, wherein said transverse incisions are V-notches at concave portions of said plates and cuts at convex portions of said plates.

5. A ski according to claim 1, wherein each of the defined voids is filled with a foamed synthetic resinous material.

6. A ski of synthetic resinous material comprising upper and lower plates combined with each other to define upper and lower surfaces of said ski, two sideplates defining side surfaces of said ski and a plurality of longitudinal ribs formed on the inner surfaces of said upper and lower plates, said ribs including transverse incisions along the axial length thereof to facilitate substantially unrestricted bending of said upper and lower plates to the required profile, said transverse incisions being V-notches at concave portions of said upper and lower plates and cuts at convex portions of said upper and lower plates, the ribs formed on said upper plate being bonded to the ribs formed on said lower plate while said upper and lower plates are maintained at the required bent profiles.

7. A ski made of synthetic resins comprising upper and lower plates combined with each other to define upper and lower surfaces thereof and two sideplates defining side surfaces thereof, characterized by a plurality of longitudinal ribs formed on inner surfaces of said upper and lower plates, said ribs being provided with such transverse incisions along the axial length thereof that allow bending of said upper and lower plates to each required profile with substantially no restriction by said ribs, the transverse incisions provided in the ribs formed on said upper plate being longitudinally shifted from those provided in the ribs formed on said lower plate, wherein said ribs formed on said upper plate are bonded with said ribs formed on said lower plate while said upper and lower plates are kept at each required bent profile. 

1. A ski of synthetic resinous material coMprising upper and lower plates combined with each other to define upper and lower surfaces of said ski, two sideplates defining side surfaces of said ski, and a plurality of longitudinal ribs successively and separately formed on each of the inner surfaces of said upper and lower plates, each of the ribs of said upper plate being oppositely disposed and bonded to a corresponding rib of said lower plate thereby defining a void between each successive pair of bonded ribs, said ribs being provided with transverse incisions along the axial length thereof to permit substantially unrestricted bending of said upper and lower plates to the required profiles.
 2. A ski according to claim 1, wherein each of said ribs has a cross section including at least two jags, the jags formed on the oppositely arranged ribs of said upper and lower plates being adapted to mesh with each other.
 3. A ski according to claim 1, wherein the transverse incisions provided in the ribs formed on said upper plate are longitudinally shifted from those provided in the ribs formed on said lower plate.
 4. A ski according to claim 1, wherein said transverse incisions are V-notches at concave portions of said plates and cuts at convex portions of said plates.
 5. A ski according to claim 1, wherein each of the defined voids is filled with a foamed synthetic resinous material.
 6. A ski of synthetic resinous material comprising upper and lower plates combined with each other to define upper and lower surfaces of said ski, two sideplates defining side surfaces of said ski and a plurality of longitudinal ribs formed on the inner surfaces of said upper and lower plates, said ribs including transverse incisions along the axial length thereof to facilitate substantially unrestricted bending of said upper and lower plates to the required profile, said transverse incisions being V-notches at concave portions of said upper and lower plates and cuts at convex portions of said upper and lower plates, the ribs formed on said upper plate being bonded to the ribs formed on said lower plate while said upper and lower plates are maintained at the required bent profiles.
 7. A ski made of synthetic resins comprising upper and lower plates combined with each other to define upper and lower surfaces thereof and two sideplates defining side surfaces thereof, characterized by a plurality of longitudinal ribs formed on inner surfaces of said upper and lower plates, said ribs being provided with such transverse incisions along the axial length thereof that allow bending of said upper and lower plates to each required profile with substantially no restriction by said ribs, the transverse incisions provided in the ribs formed on said upper plate being longitudinally shifted from those provided in the ribs formed on said lower plate, wherein said ribs formed on said upper plate are bonded with said ribs formed on said lower plate while said upper and lower plates are kept at each required bent profile. 